Got in my car this morning and it was 42 degrees when the day before it was 75. Anyways will anything bad happen if I have my CCV turned to not let the throttle body get heated when it's below 55?

 

AFAIK, that whole setup is just an emissions thing, so I wouldn't worry about it.

 

Actually, the purpose of the "heater" is to prevent the TB from icying up. MD recommends 55 deg as a safe point but I would suspect you can run it colder than that without the heat being turned on.

I closed mine a few weeks ago when temps where in the 60+ range but for the last week, then dropped back into the upper 40s/low 50s and haven't seen any problems or strange behavior.

 

I've heard that too, but it doesn't make much sense to me. Just how would a throttle body ice up under the hood, sitting atop a rapidly heating up engine, soaking up heat from a heat-soak loving aluminum plenum? How would it ice up period? Not like there's water on it to freeze.

The emissions explanation makes alot more sense. Cars polute more when first started up, until they reach operating temperature and idle down. Warming the neck of the plenum (which is where the coolant runs, not through the throttle body) heats the intake air and somehow facilitates the engine running cleaner quicker.

Beats me. I don't have to worry about it in TX.

 

Cool that's what I wanted to know. I wonder how cold it has to really be for your TB to freeze.

 

Did a quick Google search on the subject and read around a bit. Most sites state the anti-icing as the reason for it, but also state that you'd have to live in Northern Canada or someplace like that for that issue to even be a remote possibility. Some cars don't even have the feature. It's a common mod on just about any car that has it and people have been through cold US winters with no problems, so I'd say bypass it and forget it.

On a side note, I have the Kinetix v4 plenum, which comes with a separate coolant recirc block that screws to the bottom of the plenum neck. I just spaced it down with some 3/4" nylon bushings to keep it off the plenum, but the material it's made out of doesn't conduct heat very much at all (plenum gets barely luke-warmwhen the engine runs), so even with the block attached, I doubt it does anything at all. Makes me wonder why they even bothered to incorporate the feature...

 

i closed the CCV before the winter, and drove 100+ miles in 20F days, and no problems whatsoever. leave it closed.

 

does it perform better when closed?

 

It helps keep the intake plenum temperature down, so in theory, yes it helps performance.

Cooler plenum = cooler intake air = more power.

 

sorry if this is a dumb question but if the ccv is closed then how does it keep things cooler?

 

When the CCV is closed there is no coolant circulating around the TB. The dead ended lines will not heat up the plenum. When the CCV is open, coolant at 195 deg F will usually raise plenum temperature.

 

I think this thread applies to us who installed thermal management.

 

Whenever you go from atmospheric pressure to a slight vacuum, you will make the air cooler.

That is what happens when you open the throttle body when it's freezing outside... the air coming in gets a little bit cooler due to the vacuum effect of the motor. This can condense out some water vapor and make water and/or ice...

So while the motor is cold at first, if it's really cold outside it's a good idea to keep the CCV open just for safety...

 

ok so since they closed my thread down I'll just come over here. This thread only has input from one person on what temp they have had there's closed at and I wanted input from multiple people in my thread. I guess some people just feel power hungry though. Reminds me of my old school bus driver in middle school or maybe even some cops.

Anyway back to my thread... Would some of you guys be kind enough to tell me what temps you have drove yours at? And ALSO anyone who has had any problems from this. Thanks for those who want to contribute.

 

It was 32 degF this morning. I went 60 miles in about an hour with the CCV closed. Afterward, I felt the plenum out of curiosity, and it was cool except near the TB where it was COLD. The car ran great, no problem that I could discern. My mileage sucked though. Typically, I get 25+ for this trip, today it was about 23.

 

I think one thread on the CCV on page 1 of the Intake Exhaust forum is enough. Now you've been directed to the proper thread, and I might add, without any harassment or flaming on my behalf.

So kindly keep your passive aggressive comments to yourself.

 

Hahaha! You nailed it. Joul Thompson expansion! Its cool what a little physics and gas dynamics can show us.

When I had thermocouples all over the plenum during development testing, I was actually able to measure a spot on the bottom of the goose neck of the plenum just behind the TB that measured about ~5'F lower than atmospheric temperature!

This of course was only under very exact driving conditions. The throttle position and RPM had to be just right for a sustained period of time before I could measure the cooling effect. And this is why I put a fat margin on the CCV switching temperature.

But yes, I've test driven mine with the CCV closed on early frosty mornings with no adverse effects. If I lived in Alaska and drove around in a very cold blizard, I absolutely would open the valve or use the Copper throttle body heater.

 

We have a chamber in the lab that we pump down to rough vacuum regularly...

it goes from 25C to -10C in about 30 seconds just from the vacuum effect, which happens at about 40-50 mmHg (absolute pressure)

obviously the engine vacuum is no where near 50mmHg but still, the air will cool down a measurable amount

 

So, having said all that, what is the 'true' CCV switching temperature? i.e., the one with no margin? And what is at risk if one forgets to open up the CCV below this temp? Permanent damage? Or just a temporary degradation in performance until either things warm up again or s/he remembers to open the CCV?

 

+1.. The weather in TX fluctuates constantly so I have been closing/opening the CCV. I'd like to leave it closed until I come very close to the point where it's imperative that I need to open the CCV.